The official trade has Mack, a second round pick in 2020 and a conditional fifth round pick in 2020 going to Chicago in exchange for first round picks in 2019 and 2020, a third round pick in 2020 and a sixth round pick in 2019.

Shortly after being acquired, Mack then agreed to a six-year contract extension with the Bears that will pay him $141 million. Mack now becomes the highest paid defensive player in NFL history with his annual cap hit averaging out at $23.5 million per-year, and it also includes $90 million in guaranteed money.

The former standout at the University at Buffalo was drafted with the fifth overall pick by the Raiders in the 2014 NFL Draft. In his four years in the NFL, Mack has started in 64 games with 231 tackles, 40.5 sacks, nine forced fumbles and an interception. The 27-year-old has also been selected to three Pro Bowls in his young career, as well as being named a two-time First-Team All-Pro at both linebacker and defensive end. In 2016, Mack was named the AP Defensive Player of the Year with 54 tackles, 11.0 sacks, 5 forced fumbles and an interception in 16 games for the Raiders.

Mack will wear his No. 52 with the Bears, and is expected to play in the season opener on September 9 against the Green Bay Packers.